As known, the air taken in by an internal combustion engine is usually subjected to a filtration stage aimed at purifying it from the solid particles in suspension, typically dusts of various types, to prevent the latter from reaching the engine combustion chambers. This filtration stage typically occurs by means of a special filtering assembly, which is positioned along the intake conduit of the internal combustion engine, upstream of the intake manifold and of the turbocharger if present.
The filtering assembly schematically comprises an outer casing, usually referred to as filter box, which is provided with an inlet for the air to be filtered and an outlet for the filtered air, and a filtering cartridge received within said filter box for filtering the air that flows from the inlet towards the outlet. The filtering cartridge comprises at least one filtering material element, for example based on cellulose or polymeric material, and at least one plate for supporting said filtering material element. The support plate is hooked to the filter box so that the filtering material element is adapted to divide the internal volume thereof into two separate chambers, among which a first chamber communicating with the inlet and a second chamber communicating with the outlet. Thus, the air flowing from the inlet towards the outlet of the filter box is forced to traverse the filtering material element, which withholds the solid particles in suspension. Given that said solid particles progressively obstruct the filtering material element, it is commonly provided for that the filtering cartridge be removed from the filter box, so as to replace it when the filtering material element is entirely clogged.
One of the main needs related to this type of filtering assemblies lies in providing high accumulation capacity filtering cartridges, i.e. capable of withholding a large amount of solid particles before it is clogged, so as to guarantee a high useful life and thus reduce replacement interventions.
In order to address these problems filtering cartridges comprising a plurality of filtering material elements, which are arranged so as to be traversed parallel by the air flowing from the inlet towards the outlet of the filter box were proposed. Considering the use of the same filtering material, these filtering cartridges actually reveal the advantage of considerably increasing the filtering surface through which the air can pass, and hence the filtering surface on which the solid particles in suspension can accumulate.
Though being advantageous in terms of accumulation capacity, this type of filtering cartridges reveal the drawback of being quite complex to mount and being quite cumbersome. The mounting difficulty is disadvantageous in that it makes the interventions of replacing the filtering cartridge—when clogged—difficult and slow thus also increasing the costs thereof. The large overall dimension is disadvantageous in that it increases the overall dimensions of the filtering assembly which, on the contrary, should be generally small in size and/or meet precise dimensional and geometric requirements that are established by vehicle manufacturers, depending on the distribution of the volumes of all components within the vehicle engine compartment.